Node Streams

old and new

Transcript

1. Streams in Node.js the old, the new, and the why Charles Julian Knight @ c h a r l e s j u l i a n k
2. Intro Why you care: Elegant, powerful code Easy to follow Many modules use it
3. Concept: pipes "We should have some ways of coupling programs like garden hose -- screw in another segment when it becomes when it becomes necessary to massage data in another way. This is the way of IO also." -- Douglas McIlroy, 1964
4. Some examples
5. Node Streams stream.Readable stream.Writable stream.Duplex stream.Transform
6. Readable Examples f s . c r e a t e R e a d S t r e a m h t t p . I n c o m i n g M e s s a g e Implement u t i l . i n h e r i t s ( m y S t r e a m , s t r e a m . R e a d a b l e ) ; m y S t r e a m . p r o t o t y p e . r e a d = f u n c t i o n ( ) . . .
7. Writable Examples f s . c r e a t e W r i t e S t r e a m h t t p . S e r v e r R e s p o n s e Implement u t i l . i n h e r i t s ( m y S t r e a m , s t r e a m . W r i t a b l e ) ; m y S t r e a m . p r o t o t y p e . w r i t e = f u n c t i o n ( ) . . .
8. Duplex Both worlds! Example n e t . S o c k e t Implement u t i l . i n h e r i t s ( m y S t r e a m , s t r e a m . D u p l e x ) ; m y S t r e a m . p r o t o t y p e . r e a d = f u n c t i o n ( ) . . . m y S t r e a m . p r o t o t y p e . w r i t e = f u n c t i o n ( ) . . .
9. Old streams Readable o n ( ' d a t a ' ) o n ( ' e n d ' ) r e a d ( ) p a u s e ( ) r e s u m e ( ) u n s h i f t ( )
10. Old streams Writable o n ( ' d r a i n ' ) o n ( ' f i n i s h ' ) w r i t e ( ) e n d ( )
11. Let's try it!
12. Problems data comes immediately p a u s e ( ) doesn't pause handoff is difficult
13. Streams2 Implemented in v 0 . 1 0 new event: 'readable' p a u s e ( ) , r e s u m e ( ) , o n ( ' d a t a ' ) or o n ( ' e n d ' ) revert to old functionality Allows for arbitrary Objects as well as Buffers and Strings
14. Refactor!
15. And now for pipes MP3 Player s p e a k e r - takes in a stream of PCM audio data and plays it through the speakers. l a m e - Encodes/decodes MP3's to/from raw PCM formats.
16. contact charles@rabidaudio.com thanks @ s u b s t a c k @ d o m i n i c t a r r @ t o o t a l l n a t e MarkdownPresenter slides & notes speakerdeck.com/rabidaudio/node-streams github.com/rabidaudio/stream-talk